Thunderbolt Restoration

Thunderbolt Restoration Part 4 - The 1003

In reponse to my disappointment of finding a single-tone replacement rotor in the chopper of my 1000T, I put out a call for someone to please find me a dual-tone 6/5 rotor. I was never expecting to find a 1003 chopper, but that happened to be what turned up as the first available dual-tone unit. When this arrived, the hi-lo signal solenoid valve assembly was still attached, shown here.

This chopper arrived with some dents in one side of the solenoid housing, but was otherwise in great shape.

And this is the "after" shot, after about 1 hour of squishing and bending back the housing with sheet-metal vise grips, a large vise and some quick-grip clamps (handy for gentle bending).

When I opened the shipping box on receipt of this chopper, there was a big surprise, the motor! Until that moment, I had understood that all Thunderbolt choppers were based on the model 2 siren, and here in front of me now was a completely foreign looking assembly with a large c-face series motor.

I have called Federal Warning Systems for an identification on this. Pete asked around, and found that this is a Series B Thunderbolt, a short-lived attempt to modernize the design. Apparently, there were problems with this motor getting loose on the mounting plate and getting stuck out of alignment (rotor stuck to inside of stator). So, Federal quickly cranked out the Series C Thunderbolt, which was reverted to the model 2 style chopper motor. The workaround for this Series B unit is to use lock washers and retaining compound on the 4 motor-mounting bolts.

The markings you see on the rotor are notes made in permanent marker by the machinist who turned and balanced it. The condition of this rotor and the presence of the markings makes me wonder how long this siren was in service; it can't have been long.

The Federal Signal tag on this motor identifies it as a 1003ASB. 1003, 3-phase blower (A) and Series B (SB).

This is a look down into the rotor, showing the arrangement of 6 and 5 blades.